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Feb. 3, 2012 -- Teens and young adults who text frequently -- such as more than 300 text messages a day -- may be risking more than sore thumbs, according to a new study.

"Heavy texters do seem to be a little more materialistic and less concerned about inward growth," says Paul Trapnell, PhD, associate professor of psychology at the University of Winnipeg in Canada.

The frequent texting, he says, is ''weakly correlated with traits, goals, and attitudes that indicate low interest and engagement in reflective thought." Those who texted very frequently were also more concerned about wealth and image than those who did not text as often.

He conducted the study with Lisa Sinclair, PhD, associate professor of psychology at the University of Winnipeg. She presented the findings in San Diego at the 13th Annual Meeting of the Society for Personality and Social Psychology.

"Although the overall size of the finding is small in absolute terms, the finding was very reliable across several years," he tells WebMD. So far, they have looked at five years of data.

Too Much Texting: Study Details

The researchers surveyed more than 2,200 college psychology class students about their texting frequency. They were ages 18 to 22. Data were collected from 2007 through 2011.

Cell phone texting has become the preferred communication method between teens and friends, according to a 2010 report by the Pew Research Center. It found that 72% of all teens surveyed use text messaging. That's up from 51% in 2006.

For the Canadian study, the students noted how many text messages they sent or received (whichever number was higher) on their highest-use day of the month. They reported only non-work-related texts.

About 30% of the students had a peak rate of more than 200 texts a day. Twelve percent had a peak rate of more than 300 a day.

The researchers then gave them a battery of tests. These included:

A standard personality test to measure such traits as extroversion and openness to experiences.

A questionnaire that measures tendencies to engage in reflection and self-reflection: The students agreed or disagreed with such statements as, "I often love to look at my life in philosophical ways."

A survey that asked students to rate the importance of numerous life goals: Goals included wealth, fame, image, power, achievement, morality, community, family, health, spirituality, and others.

The researchers looked to see if texting frequency had an effect on the test results.

They wanted to test the so-called ''shallowing hypothesis," as described in the Nicholas Carr best seller, The Shallows, and by scientists. It suggests that very brief media social interaction such as texting encourages rapid, relatively shallow thought.

Too Much Texting: More Study Results

"Those who texted more than 100 a day were 30% less likely to feel strongly that leading an ethical, principled life was important to them," Trapnell tells WebMD. "This was in comparison to those who texted 50 or less a day."

Those who texted frequently also tended to be less reflective than those who texted less often.

The researchers cannot pinpoint a number at which the differences kick in. They found ''a general linear trend." The higher the number of texts, the greater the effect.

They looked to see if being from a higher-income home might explain the effects of placing more importance on wealth. It did not, Trapnell says.

The study has limitations, he says. For instance, naturally reflective youth may just not be into texting. They are continuing the research.

Meanwhile, Trapnell has a suggestion for those with high texting frequency: "It might be a great idea if they spent more quiet time."

The study was partially funded by the federal Natural Sciences and Engineering Research Council of Canada.

Frequent Texting and Shallowness: Perspective

The new research ties in to similar research by Mary Helen Immordino-Yang, EdD, assistant professor of psychology, education, and neuroscience at the University of Southern California. She reviewed the new findings but was not involved in the study.

In recent years, she says, scientists have focused on the brain's ''default'' mode. That refers to what the brain does when it is quiet and rested. When the brain is in this mode, she and other experts believe, it provides valuable time to reflect on life and situations. They think that downtime is important.

Distractions such as frequent texting can hamper it, she says.

"If you are habitually pulled into the outside world by distracting media, you may be systematically undermining opportunities to reflect about the moral, social, emotional, and longer-term implications of a situation," she says.

It is possible, she says, that those who text frequently are so distracted from this reflection that ''they get in the habit of thinking about things in a shallow way."

Her advice to parents of younger children who have not yet begun to text? "For healthy development, I think it is essential that we encourage our kids to have free time in which there are no distractions from TV, media, texting, you name it,'' she says.

This downtime allows kids that crucial time to reflect, she says.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.